Effect of Ru Doping on the Properties of MoSe₂ Nanoflowers

Abstract

MoSe2 is a 2D layered transition metal dichalcogenide that has attracted much attention because its properties may be easily altered by both morphology control and doping by substitutional transition metals. Here, the study of Ru-doped MoSe2 nanoflowers is presented, and the effect of Ru doping on their optical, electronic, and catalytic properties is presented. A significant enhancement in their catalytic properties toward the hydrogen evolution reaction (HER) is evident, showing an overpotential as low as 143 mV (at 10 mA cm–2) for samples by substituting 11.4% of the Mo with Ru. In order to gain understanding of the dopants’ interaction with the host and the nature of the atomic-scale substrate for the catalytic reaction, density functional theory (DFT) calculations are employed to trace the modulation of the density of states (DOS) near the Fermi level and to model possible dopant sites. The Ru dopants have two additional d electrons and a high DOS near the Fermi level. The optical absorption spectra were significantly affected by Ru doping, and the optical band gap of MoSe2 increased due to the Burstein–Moss effect. The increased charge carrier density enhances the conductance of the samples, but the most significant change is the reduction in the charge transfer resistance during the HER upon doping.

Heteroatom‐Doping of Non‐Noble Metal‐Based Catalysts for Electrocatalytic Hydrogen Evolution: An Electronic Structure Tuning Strategy

“…Comprised by the high cost of these noble metals, a low dosage use as dopants, particularly in single‐atom dispersion, is regarded as an impressive strategy. Over past decade, increasing attention has been focused on the doping of noble atoms, such as Pt, [ 86 ] Ru, [ 87 ] Rh, [ 88 ] Au, [ 89 ] into the non‐noble metal‐based catalysts to achieve optimal Δ G H* and HER activity.…”

Au-MoS2 Hybrids as Hydrogen Evolution Electrocatalysts

“…It is against this background that efforts are currently being dedicated to further modify the MoS2 structures with the aim of improving performance by increasing the density of their catalytic sites either by creating defects, [7][8][9] modifying the morphology or by doping with other transition metals. [2][3][10][11] Another approach is to combine MoS2 with other materials and produce hybrids with improved electrical conductivity, 12 more active basal planes, 13 or improved photocatalytic activity. [14][15] Recently, a study exploring the thickness dependence (number of layers) of MoS2 electrocatalysts showed a significant improvement in the catalytic activity for HER with decreasing number of layers.…”

Synthesis and characterization of WS2/SiO2 microfibers

“…The images indicate that, in analogy to the oxide fibers, two kinds of morphologies are present: fibers with rough surfaces (a) and even surfaces (b). In the fibers with rough surfaces, the flakes are arranged as nanoflowers [35], which seem to emanate from a single bulge on the oxide fiber surface. In the fibers with even surfaces, the a-b plane of the flakes is presumably parallel to the fiber surface, i.e., their caxis is perpendicular to the growth axis of the fiber.…”